Split ring valve for bore evacuator



April 16, 1968 w. H. AUSTIN, JR. ETAL 3,377,918

SPLIT RING VALVE FOR BORE EVACUATOR Filed April 21, 1966 INVENTORS Jm H .m N i a E AP A a United States Patent 3,377,918 SPLIT RING VALVE FOR BORE EVACUATOR Walter H. Austin, Jr., and Donald F. Trudeau, Troy, N.Y.,

assignors to the United States of America as represented by the Secretary of the Army Filed Apr. 21, 1966, Ser. No. 545,536 8 Claims. (Cl. 89-1) ABSTRACT OF THE DISCLOSURE A split-ring is used as a single valve to releasably seal a plurality of intake ports in a bore evacuator for cannous.

This invention relates to cannons and pertains more particularly to bore evacuator systems therefor.

With guns which are used with tanks it is important that the noxious gases be exhausted from the bore out of the muzzle after firing so that they will not enter the tank compartment when the breech is opened. The evacuator system most commonly used today consists of a cannister mounted on the tube of the gun adjacent the muzzle thereof with intake and exhaust ports leading from the bore of the tube into the chamber formed in the cannister around the tube. As the base of the fired projectile passes the intake and exhaust ports the pressurized propellant gases pass therethrough into the chamber. When the projectile emerges from the muzzle and the pressure in the chamber and tube bore equalizes, the intake ports are sealed off by valves. The smaller exhaust ports then permit the gases in the chamber to escape therefrom into the tube bore towards the muzzle, thereby inducing a low pressure region in the tube which causes a flow of air towards the muzzle when the breech is open to evacuate the fumes from the tube bore.

Design of a rugged, simple and reliable bore evacuator for cannons, firing both low and high pressure charges, has long been a problem especially as to the design of the valves for sealing OK the intake ports. Heretofore these valves have been complex as to design and they have required considerable machining of the gun tube for their installation therein.

It is therefore a primary object of this invention to provide for bore evacuators a split ring type of valve which is uniquely simple as to design, which requires little machining of the gun tube for installation therein and which is reliable in function.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a longitudinally cross-sectioned view of the bore evacuator mounted on a cannon tube and shows the split-ring valve in the closed contracted position;

FIG. 2 is a view taken along line 2-2 of FIG. 1, and

FIG. 3 is an enlarged fragmentary, longitudinally crosssectioned view showing an intake port opened by expansion of the split ring valve.

Shown in the figures is a cannon tube 12 with a bor evacuator 14 mounted thereon. Bore evacuator 14 consists of a cannister 16 which is mounted on tube 12 so as to form a pressure chamber 18 between the outside of the enclosed portion of the tube and the inside of the cannister.

Bore 20 of tube 12 communicates with chamber 18 by means of five intake ports 22, which are symmetrically located in the same cross-sectional area of the tube and which are perpendicular to the long axis thereof; and three exhaust ports 24, located forwardly of the intake ports, which are, similarly, symmetrically located in the ice same cross-sectional area of the tube and are inclined towards the muzzle end of the tube. Intake ports 22 are large enough to permit rapid pressurization of chamber 18, which must be accomplished between the time the base of projectile 25 passes the intake ports and the time it emerges from the muzzle. Exhaust ports 24 are smaller in diameter so as to exhaust the gases from chamber 18 into bore 20 at a sutficient velocity to create a low pressure in the bore and extend the exhaustion of the gases over a sufiicient period of time to purge the noxious gases therefrom.

Cannister 16 includes a rear end 26 having a sleeve 28 which receives tube 12 and makes gas tight engagement therewith as by thread means 30. Sleeve 28 includes a flange 32 which extends forwardly into cannister 16 over months 33 of intake ports 22. The inside surface 34 of flange 32 is spaced from the outside of tube 12 so as to form a channel 36 that opens forwardly into chamber 18 to provide communication between intake ports 22 and the chamber.

The flow of gas through intake ports 22 is controlled by a valve 38 of split-ring type which encircles tube 12 within channel 36 so as to cover mouths 33. The radius of valve 38 when in its normal contracted state is less than that of the contacted section of tube 12 so that the valve when contracted, or closed, firmly contacts the tube to seal intake ports 22. Spaced symmetrically around the inside of valve 38, so as to extend inwardly therefrom, are six pairs of tangs 42 which are longitudinally spaced so as to be received by a cooperating pair of grooves 44 respectively formed in tube 12 fore and aft of months 33 to prevent longitudinal displacement of the valve, relative to the tube, while permitting expansion thereof. The expansion of valve 38 is limited by the contact thereof with inside surface 34 of flange 32. Inside surface 34 is so spaced from valve 38, when contracted, that the expansion thereof is stopped before tangs 42 are clear of grooves 44. A lug 46 on tube 12 is received between the spaced ends 48 of valve 38 to prevent rotational displacement thereof on the tube.

Operation As the base of fired projectile 25 passes intake port 22, the propellant gases enter thereinto and the pressure of the gases, acting against the underside of valve 38, causes the valve to expand and open months 33 for passage of the gases through channel 36 into chamber 18. As projectile 25 passes exhaust ports 24, the propellant gases flow therethrough also to aid in pressurizing chamber 18. During pressurization of chamber 18, valve 38 is retained in place by tangs 42, inside surface 34, and lug 46.

When projectile 25 emerges from the muzzle of tube 12, the pressure in bore 20 decreases, thereby permitting valve 38 to contract and close intake ports 22 when the pressure in the bore and chamber 18 are equal. When valve 38 closes and the pressure of the gases in bore 20 becomes less than that in chamber 18, the gases in channel 36 assist in sealing the valve tightly over ports 22. Thus, the gases in chamber 18 can escape therefrom only through exhaust ports 24 which, by being inclined forwardly, produce a low pressure area in bore 20 and thereby air is moved through the bore towards the muzzle from the breech, when opened, for evacuation of the fumes from the bore.

We claim:

1. The combination including a cannon tube with a bore, a bore evacuator including a cannister mounted on said tube to form a pressure chamber around the inclosed section thereof, a plurality of exhaust ports providing communication between the chamber and bore, a plurality of intake ports providing communication between the chamber and bore, and a valve of split-ring configuration mounted on said tube to releasably seal said intake ports against passage of pressurized gases from the chamber into the bore.

2. The combination as defined in claim 1 wherein said valve is arranged to be displaceable between a closed contracted position wherein said valve firmly contacts said tube around the cross-sectional area thereof including said intake ports and an expanded open position spaced from said tube to permit passage of pressurized gases from said intake ports into said chamber, and wherein said valve and said intake ports are so arranged that when gas pressure in the bore is greater than that in the chamber said valve is expanded thereby to the open position.

3. The combination as defined in claim 2 and including means on said cannister for stopping further expansion of said valve past the open position, and cooperating tang and groove means on said valve and in said tube for preventing longitudinal displacement of said valve thereon.

4. The combination as defined in claim 2 wherein said exhaust ports are located forwardly of said intake ports in said tube and said cannister includes a rear end with a collar having gas tight engagement with said tube, a circular flange extending forwardly from said collar around said tube over mouths of said intake ports and spaced from said tube, a channel formed between said flange and said tube to receive said valve and provide communication between said intake ports and the chamber.

5. The combination as defined in claim 4 wherein said flange is spaced from said tube so as to stop expansion of said valve beyond the open position, and so that pressurized gases in said chamber are actuatable against said valve to assist in holding said valve in the closed position and sealing said intake ports.

6. The invention as defined in claim 5 and including tang means on said valve, and grooves in said tube for receiving said tang means to prevent longitudinal displacement of said valve thereon.

7. The combination including a cannon tube with a bore, a bore evacuator including a cannister mounted on said tube to form a pressure chamber around the inclosed section thereof, a plurality of exhaust ports providing communication between the chamber and bore, a plurality of intake ports providing communication between the chamber and bore, a valve of split-ring configuration mounted on said tube to releasably seal said intake ports against passage of pressurized gases from the chamber into the bore, spaced ends on said valve formed by the split configuration thereof, and a lug on said tube disposed between said spaced ends to prevent rotational displacement of said valve on said tube.

3. The combination including a cannon tube with a bore, a bore evacuator including a cannister mounted on said tube to form a pressure chamber around the inclosed section thereof, a plurality of exhaust ports providing communication between the chamber and bore, a plurality of intake ports located rearwardly of said exhaust ports and arranged to provide communication between the chamber and bore, a valve of split-ring configuration mounted on said tube to releasably seal said intake ports against passage of pressurized gases from the chamber into the bore, said valve being displaceable between a closed contracted position wherein said valve firmly contacts said tube around the cross-sectional area thereof including said intake ports and an expanded position spaced from said tube to permit passage of pressurized gases from said intake ports into said chamber, said valve 7 and said intake ports being so arranged that when gas pressure in the bore is greater than that in the chamber said valve is expanded to the open position, said cannister including a rear end with a collar having a gas tight engagement with said tube, a circular flange extending forwardly from said collar around said tube over the mouths of said intake valves and spaced from said tube, a channel formed between said flange and said tube to receive said valve and provide communication between said intake ports and the chamber, said flange being spaced from said tube so as to stop expansion of said valve beyond the open position and so that pressurized gases in said chamber are actuatable against said valve to assist in holding said valve in the closed position and sealing said intake ports, spaced ends on said valve formed by the split configuration thereof, and a lug on said tube disposed between said spaced ends to prevent rotational displacement of said valve on said tube.

References Cited UNITED STATES PATENTS 2,779,241 1/1957 Howard et al. 891 2,807,986 10/1957 Howard et al 89-4 BENJAMIN A. BORCHELT, Primary Examiner. 

